1. Field of the Invention
Aspects of the present invention relate to a computer system and a control method, and more particularly to a computer system with high use efficiency for a large number of usable devices without restriction on the size of the computer system.
2. Description of the Related Art
At present, computer systems have made rapid progress in their performance owing to higher speed CPUs and higher speed buses such as PCI-Express, USB2.0, IEEE 1394, etc. However, PATA (Parallel Advanced Technology Attachment), which is fixed at a maximum of 133 MB/s, is an obstacle to further development of computer system performance. In recent years, SATA (Serial Advanced Technology Attachment) has been proposed to overcome this obstacle. SATA operates at a maximum of 1.5 Gbps, and further, SATA-II may operate at a maximum of 3.0 Gbps. Also, since SATA (or SATA-II) performs communication via a communication cable using fewer signal pins than PATA, it has merit in that a mounting connector for mounting devices supporting SATA is very small and occupies less space on a board, as compared to PATA.
By virtue of this merit, SATA HDDs (hard disk drives) are rapidly being popularized as SATA devices supporting SATA. Control of a conventional computer system including a SATA HDD as representative devices mounted inside the computer system will be hereinafter described in brief with reference to FIG. 1. As shown in FIG. 1, the conventional computer system includes an ICH (input/output control hub) 1 for interconnecting input signals among various peripheral devices in the computer system and a mounting connector 2 for mounting a SATA HDD 3 supporting a SATA interface standard in such a manner that the SATA HDD 3 may communicate with the ICH 1. Then, when the computer system is powered on, the ICH 1 can communicate with and control the SATA HDD 3 mounted in the mounting connector 2.
With the growing numbers of SATA devices supporting SATA, the ICH 1 shows a tendency to include a plurality of communication channels CH1, CH2, and CH3, which may communicate with the SATA devices, as shown in FIG. 1. Thus, when it is designed for one (for example, CH1) among the plurality of communication channels of the ICH 1 to be connected to the mounting connector 2, the ICH 1 can communicate with the SATA HDD 3 mounted in the mounting connector 2 via a TX port and an RX port of the communication channel CH1.
However, an internal device, such as the SATA HDD 3, mounted on a board of the computer system through the mounting connector 2 provided inside the computer system cannot operate since the internal device is not supplied with power when the computer system is powered off. That is, when the computer system is powered off, there is no way for other external computer systems to access the internal device (for example, the SATA HDD 3) mounted inside the computer system.
Particularly, a small computer system such as a notebook computer has a very limited size and hence a limitation on the number of devices (e.g., SATA HDD) mountable on an internal board. Therefore, when a computer system is powered off, if the other computer system can access and use a SATA HDD mounted inside the powered-off computer system, it allows the other computer system, which is powered on, to efficiently use the increased number of usable devices without a restriction on the computer system's size.